Alarm mechanism



E. A. FALLER ALARM MECHANI'SM March 24. 1925.

2 Sheets-Sheet 2 E. A. FALLER ALARM Mscmmrsn Filed sept. g5. 1918 March 24, 1925.

jizz/522ml'.

I Patented Mar. 24, 1925.

UNITED STATES PATENT OFFICE.

ERNEST A.. FALLER, OF BROOKLYN, NEW YORK, ASSIGNOR T MEAD ELECTRIC SIGNAL COMPANY, 0F CLEVELAND, OHIO, A CORPORATION 0F OHIO.

lALARM MECHANISM.

Application filed September 25, 1918. Serial No. 255,629.

To all whom it lmay concern.' Be it known that I, ERNEST A. FALLER, a. citizen of the United States, residing at Brooklyn. in the county of Kings and State of New York, have invented certain new and useful Improvements in Alarm Mechanism, of whichthe following is a specification.

This invention relates to alarm' mechanism such as is used in ire alarm, telegraph,

messenger call and other similar systems.

The object of the invention is to generally simplify and improve the construction and operation of the call device, thereby to reduce its cost and secure more efficient operation. More specifically, the invention has for its objects to improve and simplify the escapement mechanism, to provide an improved mounting for the code wheel, to provide mechanism which insures full winding of theclock mechanism before its release to actuate the call device, and to provide for sendingtest signals over the line without operating the call mechanism or for testing the call mechanism without affecting the line, as is required in systems of this character.

Further objects of the invention are in part obvious and in part will appear more in detail hereinafter.

The invention comprises the mechanism hereinafter described and claimed.

In the drawings, which represent one suitable embodiment of the invention, Fig. 1 is a front view of the call mechanism, the outer enclosing casing being omitted for clearness of illustration; Fig. 2 is a side elevation from the right in Fig. ,1, a portion of the enclosing casing being shown in section; Fig. 3 is a sectional elevation on the line 3 3, Fig. 2, looking in the direction of the arrows; Fig. 4 is a detail cross section on the line 4 4, Fig. 3; Fig. 5 is a detail section on the line 5 5, Fig. 3, looking in the direction of the arrows; Fig. 6 is a front elevation, illustrating a .portion of the enclosing casing, with the circuit contacts in dotted lines therebeneath; Fig. 7 is a similar view, illustrating a test key in operative position; Fig. 8 is a detail section on the line 8 8, Fig. 7; Fig. 9 is a detail sectional view of one end of the key; and Fig. 10 iS a, detail section on the line 1 0-1 0,

Fig. 2, parts being omitted for clearness of illustration.

`Referring to the drawings, the call mechamsm comprises a suitable frame usually formed of two parallel metal plates 1 held apart by spacing sleeves 2 surrounding the clamping bolts 3, said plates having the necessary holes to form bearings for the spindles, and brackets to support other parts of the mechanism, as will appear. Journalled in said plates is a spindle 4 which serves as a winding Shaft for the power spring 5, which is in the form of the usual coiled spring inclosed in a drum 6, the inner end of the spring being connected to shaft 4 and the outer end to the drum, so that the spring exerts a constant tendency to turn the drum in the direction indicated by the arrow A, Fig. 3. 7 is a holding pawl pivoted to the frame plate 1 and held yieldingly by a spring 8 in engagement with the teeth of a ratchet 9 fast on the shaft 4.

Drum 6 has attached thereto or is formed to provide a gear 10 whose teeth engage the teeth of a pinion 11 on a code wheel shaft 12, said shaft also carrying a second gear 13 to operatively connect it to the escapement mechanism which controls the application of power to the mechanism and limits the speed of rotation of the code wheel. This escapement mechanism comprises a spindle 14 carrying a pinion 15 whose teeth engage the teeth of gear 13 and an escapement wheel 16 having pointed teeth, as illustrated in Fig. 3. The teeth of escapement wheel 16 co-operate with two pins 17 projecting outwardly from one end face of a short cylinder or thick disc 18 attached to a shaft 19. The escapement operates in the usual manner of such devices, the teeth of wheel 16 engaging first one end and then the other of the pins 17, and the co-operation of said pins alternately with the teeth of the escapement wheel produces reciprocatory rotary motion or oscillation of the disc 18, and therefore limits the speed of rotation of the parts.

While any suitable form of escapement device is suitable for the purpose I prefer to employ the form shown in the drawings, in which escapement member 18 and its at'- tached parts' are of peculiar construction 105 designed to simplify manufacturing operations and secure more eficient operation. As illustrated in Fig. 5, the pins 17 are the opposite ends of a U- shaped wire staple which can be made from hard Wire by a simple forming operation in such manner as to secure accurate spacing between the two pin ends 17. The shaft 19 has its central portion suitably deformed into noncircular shape, such as by inching outl one or two wings 20 thereon. l aid Ishaft and the staple forming the two pins 17 are then held in proper position in a small mold and the metal to form the disc 18 is cast into said mold, so that it flows around the shaft and staple and not only` secures them rigidly to each other and to the disc but also preserves the proper position and spacing of the pins 17 The bodyf- 18 is, of course, made of the proper size and weight to exert the necessary retarding effect upon the escapement mechanism.

Shaft 12 carries the code wheel, and the mounting for said Wheel is of special form designed to insure the securement of the wheel in the proper position to said shaft, to pre-` vent its displacement on the shaft and to enable the code wheel to be readily changed when desired. As illustrated, the code wheel 21 has the usual code teeth 22 upon its periphery, two sets of said teeth being provided on opposite sides of the wheel center. The wheel is provided with a radially extending slot 23 passing beyond its center, one portion of the wall of the slot at its inner end being counter-sunk at 24. Said wheel is held against a suitable abutment, such as a rigid dise or collar 25 of the shaft 12 and is secured thereto by two screws 26, 27, which pass through a clamping disc 28 and thence through the slot 23 and are threaded into the disc 25. One of the screws, marked 27, has an enlarged shoulder 29 beneath its head, which fits in a larger opening in the disc 28 than the shank of screw 26, and which also fits in the counter-sunk portion 24 of the code wheel. With this arrangement the two screws 26, 27 absolutely prevent rotation of the code wheel upon the shaft 12 when secured thereto, the construction being far more positive in this regard than the usual set screw passing through the hub of the code wheel, which is the common construction. Furthermore, the varrangement insures setting of the code wheel on the shaft in the proper position and avoids the possibility of accidentally shifting it 180, because the two screws 26, 27 diifer from each other and the code wheel will only go in in one position. The slot 23 also enables the code wheel to be readily pulled out cross-wise of the shaft by merely loosening the clamping screws, which can be reached with `a screw driver through holes 1 in the plate 1. v

As is usual,- the code wheel co-operates with a set of contacts-in a line to the central' wires 35 to the central station, and the system operates upon the closed circuit principle, current normally traversing the line. In other words, the normal position of the parts is illustrated in Fig. 1, contacts 30 and 31 being in electrical contact with each other so that the circuit is closed. As the code wheel revolves its teeth 22 successively engages the arm 33 and moves the contact 31 to the left in Fig. 1, thereby opening the circuit and producing an audible, visible or other signal effect upon an instrument at the central station. The particular code wheel shown revolves in the clock-wise direction, Fig. 3, and sends out the signal 21 twice at each complete revolution ofthe codev wheel.

On the shaft 4 is a radial projection 36 cooperating with a pin 37 on the wall of the drum 6. This projection and pin limit the effect of the main clock spring. When the spring is wound by turning the shaft 4 the shaft projection. 36 is moved in advance of and away from the drum pin 37. The spring then turns the drum and actuates the clock mechanism until pin 37 overtakes and engages the projection 36,. in which position the two ends of the spring are rigidly connected through the projection 36 andpin 37 and the spring becomes ineffective upon any of the call mechanism, none of the gears or shafts of which are then under torque. Another pin 37a may be also secured in the wall of the drum, a little in excess of ninety degrees in advance of pin 37, in the direction ,of winding. This permits of a movement of turns said shaft approximately 90, the ratio of the gearing being such that 90 movement of the drum 6 turns the code Wheel through two complete revolutions. Therefore, a single winding of the instrument produces four calls or signals at the central station.

For winding the shaft 4 it is provided at one end with a sleeve 38 carrying an arm 39 on which is a spring pawl 40 co-operating with the teeth of ratchet 9. Sleeve 38 also has secured thereto an arm oirhandle 41 to -which is connected a spiral spring 42 whose opposite end is fastened to a stationary post 43, the tendency of the spring being to turn the handle in the clock-.wise direcmon, Fig.

1. When the handle 41 is pulled down or to the left in Fig. 1, a full stroke, or a little over 90, the main spring is Wound up one step, as before described, and the pin 37i prevents further motion of the winding shaft until the drum has made a complete quarter turn. Y Of course, the Winding lever can be moved through a greater or lesser arc .While the mechanism is running and transmitting a signal, but it will be impossible to move the lever 41 through an arc sutlicient to engage the next tooth of the ratchet. This arrangement insures winding of the main spring to the same tension at each winding l operation.

Suitable means is also provided for insur!7 ing a full stroke of the operating lever 41 before the drum is released to actuate the code wheel. As indicated, the sleeve 38 car ries a cam 44 co-operating with oppositely disposed pins 45 on the yoke portion of an arm 46 carried by a shaft 47 mounted 1n the frame plates, and which shaft is pro-s vided with a second arm 48 having a foot or locking portion 49 (3o-operating in turn with a series of four spaced pins 50 carried by the drum gear 1,0. The normal position of the parts is illustrated in Fig. 10, foot 49 being out of the path of movement of. the pins 50. Cam 44 has quick acting portions 51 adapted during the very first portion of the stroke of the lever 41 to move over the arm 48 so that the foot 49 is in the path of movement of the pins 50. Consequently', said foot serves as a stop to prevent release of the drum 6 for movement. The next portions of the cam, marked 52, hold the foot 49 in operative range of the pins 50, but inally, during the last portion ot the stroke of the lever, other parts 53 of the cam move the arm 48 back to its original position and thereby release the pin 50. Release of the pin occurs after the spring has been fully Wound one step, so that a new tooth of the ratchet 9 has passed beyond the holding pawl 7. As soon as the pin 50 is released the drum" begins to turn and actuates the call mechanism. The lever 41 can then be immediately released as the pin 50 has then passed beyond the range of the foot 49 and the latter can return to its normal position without eii'ect upon the spring drum.

The instrument so far described is usually enclosed in somel form of casing in such manner that only the outer end of the sleeve 38 and the operating lever 41 are outside of said casing. This casing requires no special description, the only portion thereof shown being indicated at 54, which represents that wall of the casing lying parallel to the outer frame plate 1. Opposite the space or cavity between the two contacts springs 30, 31 this wall 54 of the casing is provided with a suitable guide, such as a thimble 55, through the opening 55a in which a' test key may be inserted into'co-operating relation with said contacts. Preferably, the test key is of peculiar form and the opening 55a is designed to receive it. For example, opening 55a has a central round portion and two wings or slots 56 connected therewith. Opening 55 is smaller in diameter than the space between the contacts 30, 3l, while the slots 56 lie parallel with said contacts. Therefore, it is impossible to reach the contacts with a nail or similar round rod or with a fiat plate inserted through the opening or slots.. The test key has a body portion 57 made of insulating material and carrying a central collar 58. This collar abuts the outer surface of the casing when either end of the key is inserted into operative relation with the electrical contacts. The insulating material at one end of the body carries two oppositely disposed Wings or prongs 59 also of insulating material. At its opposite end the body is threaded to receive a m'etal sleevef'60 provided with metal Wings 61. The insulated or nonconducting end of this key may be termed the dead end and its metal or conducting end the live end. Either end of the ke may be inserted into the key hole 55'L and1 the key turned until the wings thereof abut and spread apart the contacts 30, 31. When the dead end is inserted electrical connection between the two contacts is broken, and the same efect is produced at the central station as though one of the teeth of the code wheel had passed the operating arm 33. With this end of the key it is therefore possible to send a signal over the line without actua tion of the call mechanism. If the other end of the key is inserted and the key turned the contacts are separated but without electrically disconnecting the same, as the 'circuit across said contacts is maintained by the metallic portion of the key, and, moreover,

the parts are so spread and are placed under such tension, that the teeth 22 of the code wheel, even though engaging the arm 33 are unable to break the contact. With the key in this position, therefore, it is possible to actuate the call mechanism without breaking the electrical connection to the line. The key therefore enables the line to be tested independently of the call mechanism or the call nechanism to be tested independently of the ine.

What I claim is:

1. In alarm mechanism, a code wheel shaft having an abutment, a code wheel having a radial slot to receive said shaft, and a screw extending parallel to said shaft through said slot into said abutment for clamping said wheel against said abutment.

2. In alarm mechanism, a code wheel shaft having an abutment, a code wheel having a radial slot to reoevead shaft, said slot u' extending from the periphery of said wheel beyond its center, and two screws passlng through said slot, one on either side of said lshaft, for securing said Wheel to said abutment.

3. In alarm mechanism, a code wheel shaft having an abutment, a code wheel having a radial slot to receive said shaft, said slot extending from the periphery ofsaid wheel beyond its center, and two screws passing through said slot, one on either side of said shaft for securing said wheel to said abutment, one ot' said screws having an enlargement upon its shank, and said wheel having a counter-sunk portion to receive the same.

4. In alarm mechanism, a code wheel shaft having a collar, a washer loose on said shaft adjacent said collar, a code Wheel having a radial slot and thereby adapted to be placed upon said shaft between said washer and collar, and a securing screw for said wheel extending parallel with said shaft through said washer and the slot in said Wheel into said collar, whereby the wheel may be rethrough -said Washer and the slot of sai wheel and threaded into said collar.

6. In alarm mechanism, a code wheel shafthaving a collar, a washer loose on said shaft adjacent said collar, a code wheel having a radial slot and thereby adapted to be placed upon said shaft between said Washer and collar, and two securing screws passing through said Washer and the slot of said Wheel and threaded into said collar, one of` said screws having an enlarged shank, and said wheel having a counter-sunk portion to receive the same.

p In testimony whereof I aiiix my signature.

ERNEST A. FALLER. 

